Redox reaction of PEO modified cytochrome c adsorbed on the electrode in ion conductive PEO matrix analyzed with non-contact optical waveguide spectroscopy

Optical waveguide spectroscopy was used under non-contact conditions to analyze the visible absorption spectrum of poly(ethylene oxide) (M _w = 150) modified cytochrome c (PEO₁₅₀-cyt.c) adsorbed on an indium tin oxide (ITO) glass electrode. The redox reactions of the adsorbed PEO₁₅₀-cyt.c were dynamically measured in situ in PEO oligomers (M _w = 200). It was confirmed that PEO modification of cyt.c is effective in maintaining the redox activity of the cyt.c after adsorption on the ITO glass electrode. The PEO₁₅₀-cyt.c adsorbed on the electrode re-dissolved gradually in PEO oligomer. Against this, PEO₁₀₀₀-cyt.c having longer PEO chains (M _w = 1000) was found to be adsorbed stably on the electrode. Copyright © 2003 John Wiley & Sons, Ltd.